Surface grinder



Oct. 3, 1961 P. M. ADAMS 3,002,323

SURFACE GRINDER Filed April ll, 1955 3 Sheets-Sheet 1 PARKS M. ADAMSINVENTOR.

ATTORNEY N In FIGS

TTTTTT EY P. M. ADAMS SURFACE GRINDER Oct. 3, 1961 5 Sheets-Sheet 3Filed April 1l, 1955 PARKS MADAMS INVENTOR. BY C]d Www ATTORNEY3,002,323 SURFACE GRINDER Parks M. Adams, 1211 Stevenson Lane, Towson,Md. Filed Apr. 11, 1955, Ser. No. 500,365 6 Claims. (Cl. 'S1- 102) Thepresent invention relates to grinders and more particularly to that typeknown `as surface grinders. This type of grinder is especially adaptedto the type of operation used to provide a dat surface at the matingsurfaces of cylinder blocks and heads, but may also be used for othertypes of work where a smooth and flat ground surtace is required.

Although there are many types of surface grinders already existing, nouehas yet been provided which will satisfactorily grind such items ascylinder blocks and heads, but which is relatively simple inconstruction and capable of producing a high quality of groundsurface.Because the mating surfaces of a cylinder block and its head must besubstantially at, in order to provide a satisfactory seal with the thinhead gasket, it is often necessary, when reconditioning an automotiveengine, to regrind the cylinder head and the block. Because thecharacter of the ground surface depends largely upon the speed of thegrinding wheel, the vrate at which the work is fed to the wheel, and theamount of material removed in each pass of the work across the Wheel, ithas previously been difficult to obtain a satisfactory surface withoutthe use of an elaborate grinding process.

It is the object of this invention, therefore, to provide a simple,economical and practical grinding machine which will produce ya true andflat surface without the use of elaborate grinding techniques. n

It is another object of this invention to provide a grinding apparatuswhich will permit the use of a high speed grinding wheel.

In the drawing:

FIGURE l is -a plan view of the machine contemplated by this invention.

FIGURE 2 is a side elevation view ofthe machine.

States Pate t FIGURE 3 is an enlarged fragmentary sectional view takenalong line 3--3 of FIGURE 1.

FIGURE 4 is an enlarged sectional view taken alon line 4-4 of FIGURE l.

FIGURE 5 is a fragmentary detail view of the grinding wheel bearing andits adjustment.

FIGURE 6 is a sectional view taken along line 6 6 Yof FIGURE 2 andshowing the concave curvature of the work table of the machine.

The grinding machine, as shown in FIGURES l and 2, is composed of a basel which is mounted upon suitable legs or supports 2. A pair of work;supporting plates 3 and 4 are carried on the base 1 to form a worktable. The adjacent edges Z5 and 26 of the plates 3 and 4 respectively,are cut diagonally and spaced apart to form a diagonal slot extending-across the grinding table as shown in FIGURE l. The outer edges of vZ7and 28 of the plates are arranged higher than the diagonal inner edgesso that the plates slope inwardly toward the opening, the amount of theslope being generally less than .002 inch per foot. The slope of theplates has been exaggerated in the drawing for illustrative purposes.

A pair of side rails 5 and 6 extend one along each side of the supportplates 3 and 4 and an adjustable guide 7 is carried by side rail 6 toprovide a guide for the work during the grinding operation. Guide '7 iscarried by a group of members 8, 9, 10 and l1 which pass throughsuitable apertures in side rail 6 and are secured in position by setscrews 12, soi that the guide may be adjusted laterally and secured inposition as desired.

Positioned diagonally across the work table in the slot between plates 3and 4 is a suitable grinding wheel 13 of comparatively small diameterwhich is adjustable vertically relative to the upper surface of plates 3and 4. The grinding wheel is mounted on a shaft 14 which is supported inbearings 15 and 16 at each Side of the Work table.` The bearings aremounted in adjustable bearing blocks 17 and 18 respectively, which arein turn suitably supported for vertical. adjustment in frames 19 and 20.Adjustment is eiected, as best shown in FIGURE 5, by means of a handWheel 21 which is fixed to the lower end of the shaft 22. The shaftthreadedly engages the lower portion of frame 19 and the upper end ofthe shaft engages the lower portion of the bearing block 17' so thatrotation of the shaft by means of hand wheel 21 is effective to move thebearing block vertically within the frame 19. Shaft 2.2 also carries asprocket wheel 23. A similar arrangement is provided at the other sideof the Work table to provide for adjustment at the other end of thegrinding wheel shaft :14. A chain 24 extends between and engages thesprocket wheels so that both ends of shaft 14 may be simultaneouslyadjusted by rotation of hand wheel 2l. n

The grinder may be powered in any suitable manner, the arrangementdepicted in the drawings consisting of a motor 29 which is set at lanangle to the table and supported so that its drive shaft 30 is parallelto the shaft 14 whi-ch carries the grinding wheel 13. V-pulleys 31 and32 are mounted on shafts 14 and 30 respectively, and carry a V-belt 33.Idler 34 is provided to take up the slack in belt 33, which is made longenough to allow vertical adjustment of the grindingwheel 13.

Since the best ground surface is provided by a high speed grindingwheel, and the maximum permissable feed and depth of cut is limited bythe heat generated by the cutting action of lthe grinding wheel, it isgenerally not possible to complete the grinding operation in one passacross the grinding Wheel. Thus, previous attempts at a simplified formof grinding mechanism which utilize the wood planer principle of settingthe two halves of the work table on different levels on opposite sidesof the grinding wheel have not been successful since such an arrangementdoes not allow the work to be returned across the grinding wheel afterthe initial pass. That is, if more than one pass is needed to grind ofrthe desired amount of material, it is necessary to remove the work fromthe table after the initial pass and reposition it for each subsequentpass across the grinding wheel. If both halves of the Work table in sucha machine are set at the same level to allow the work to pass in bothdirections, satisfactory results still cannot be obtained because thereis no support for the ground portion of the work once it has passedacross the grinding Wheel. Obviously, when using suc-h a machine, sincethe center of gravity of an object being ground generally lies at ornear the mid-point thereof, relatively greaterv grinding pressure willbe exerted by the weight of the object when the center of gravity isdirectly over the grinding Wheel thanwhen the ends of the object arepassing over the wheel, causing more material to be removed from thecenter of the'work than from the ends, and producing a concave surface.

To eliminate this difculty, the machine herein proposed has its Worksupporting plates 3 and 4 arranged as hereinbefore described so as toslope inwardly toward the grinding wheel at an inclination of .002. perfoot or less, slopes within this range having been found byexperimentation to give the desired result. As may be seen in FIGURE 3,as the work 35 passes across the grinding wheel, it is supported at itsextreme ends on the upper Vsurfaces of the inclined suporting plates3.and 4, so that as the center of gravity of the work approaches thegrinding wheel, the position of the points of support with relation tothe wheel changes to support the worl; at the proper height above thewheel to allow substantially the same amount of material to be removedfrom the center of the work as from the ends. The amount of slopenecessary to provide a uniform grinding pressure across the entiresurface being vground will vary with the length, thickness and type ofmaterial of the object being ground, vand can be determinedexperimentally. Experience -with machines constructed in accordance withthis invention jhas shown that Acylinder heads, blocks `and similaritems Vcan be ground lby theuse of this method to have a fiat surfacewell within the tolerance necessary for providing a goodv seal whenyassembled with a conventional cylinder `head gasket.

When reconditioning used cylinder heads an dblocks, it is sometimesdesired to grind the surface in such a ymanner as to remove more fromone side than the other in order to make the surface true. This iseasily accomplished in the herein contemplated machine by use of thearrangement depicted in .FIGURE 6. Work supporting plates 3` and 4 areformed so that their upper surfaces are concave as shown, the amount ofcurvature being exaggerated in the drawings for clarity in illustration.By adjustment of guide 7, the lateral position of the work may beselected so `that the work is suported on the plates 3 fand `4 with oneside of the work higher than the other by any desired amount within thelimits of the .concavity of the plates. Thus, the surface of the Workmay be corrected for any lateral deviation in tnleness simultaneouslywith the normal grinding operation.

The above arrangement is also effective when the object being ground isheavier atone side than at the other, as is the case with cylinder headsin which the cylinders are disposed along one side of the head. Whensuch objects are ground, a relatively greater grinding pressure will beexerted at the heavier side as the work passes over `the grinding wheel,causing more material to be removed from that side than from the other.This condition may be compensated for by selecting the proper lateralposition for the work as above described.

Although in the drawings the grinding wheel is depicted as beingarranged at an angle with the direction of motion of the work across thewheel, it is to be understood that the wheel may be arranged so as to beperpendicular to the line of motion, the angular arrangement beingselected to give the most satisfactory character to the ground surface.

A machine constructed and operated in accordance with the principlesherein set out will grind a true and at surface within very closeto-lerances, and will permit the most advantageous combination ofgrinding wheel speed, work feed and depth of cut by allowing the work tobe passed back and forth across the grinding wheel` the required numberof times to remove the necessary amount of material, thereby overcomingthe limitation inherent in planer type machines having work suportingtables set at different levels and which, therefore, yare limited to asingle pass during the grinding operation.

While but ,one embodiment of the present invention has `been shown anddescribed, it is to be understood that relongated opening formedtherethrough, the upper surface of said table being formed in two halveseach extending outwardly from said opening and sloping upwardlytherefrom, each said half of said upper surface being concavely curvedin a direction normal to the slope of said upper surface, a cylindricalgrinding element mounted within said opening and vertically adjustablewith respect to said upper surface of said table, and means for'rotating said grinding element.

2. A machine comprising, means forming an elongated table having atransverse slot formed therein,

the upper surface of said table being divided into two portions by saidslot, each said portion being sloped from said slot upward to the outerend of said portion, each said portion being concavely curved in adirection normal to the slope of said surface, cylindrical grindingmeans mounted within said slot ,and vertically adjustable with respectto said upper surface, and means for rotating said grinding means.

3. A grinding machine comprising, an elongated table forming an uppersurface having an elongated opening extending therethrough, said uppersurface being formed in two portions extending outwardly and upwardlyfrom each side of said opening, the imaginary intersection of said twoportions of said upper surface being generally transverse tothelongitudinal axis of said table, each said portion of said suppersurface being concavely curved about an axis parallel -to the slope ofsaid surface, a high speed cylindrical grinding element of relativelysmall diameter mounted within said opening between said two portions ofsaid table and having its axis extending transverse to the longitudinalaxis of said table and lying in a plane below said imaginaryintersection, and power means connecting with said grinding element andoperative to ,effect rotation thereof.

4. A grinding machine comprising, an elongated table having an uppersurface and a narrow opening extending therethrough, the upper surfaceof said table being formed in two portions extending outwardly fromopposite sides of said opening and sloping upwardly therefrom at aninclination off not `more 'than .002 of an inch per foot,

'eachsaid surface being concavely and similarly formed about an axisparallel to the direction of said inclination, a cylindrical grindingelement of relatively small diameter mounted within said opening andhaving a supporting shaft extending entirely through the cylindricalaxis of said grinding element, a bearing at each end of said opening toreceive said shaft, vertically ixed guideways extending downwardly fromthe table for slidably receiving the bearing, means for simultaneouslyelfecting vertical adjustment of both bearings relative to said table,and Vmeans connecting with said shaft for rotating said grindingelement.

5.r In a grinding machine, the combination of an elongated table havinga continuous upper surface and a narrow opening extending transverselytherethrough, the upper surface of said table being formed concavelyabout an axis parallel the longitudinal axis of said table, acylindrical grinding element rotatably carried within said opening, andwork guide meansextending substantially parallel to said longitudinalaxis and laterally adjustable with respect thereto.

6. In a grinding machine, the combination of an elongated table havingan upper surface and a narrow opening extending transverselytherethrough, the upper surface of said table being formed in twoportions extending upwardly and outwardly from opposite sides of saidopening yat an inclination of not more than .002 inch per foot, said twoportions of the upper surface of said table being concavely curvednormal to the direction of said inclination, and a cylindrical grindingelement rotatably carried within said opening.

References Cited in the Ele of this patent UNITED STATES PATENTS 857,757Reid June 25, 1907 1,197,435; Bogue Sept. 5, 1916 1,961,487 Hamann June5, 1934 2,598,020 Rutherford May 2.7, 1952 FOREIGN PATENTS 13,227 GreatBritain July 23, 1900 12,712 Great Britain 1909

